How to parse a string array into a multidimensional array?

Use explode() to separate the key ( $str[0] ) and the value ( $str[1] ) of each item in the array, after combining the pair and assigning that element to the new array.

$arr = ['MemTotal:        4060964 kB',
        'MemFree:         3630320 kB',
        'MemAvailable:    3789472 kB',
        'Buffers:           93040 kB',
        'SwapCached:            0',
        'Active:           306312 kB'];

$novo = array();
foreach($arr as $item){
    $str = explode(':', $item);
    $novo[$str[0]] = trim($str[1]); 
}

In this example, I kept the same object.

Original indexes are removed as they are "converted"

$arr = array(
    'a:     1',
    'b: 4',
    'c:   2',
);

print_r($arr);

foreach ($arr as $k => $v) {
    $a = explode(':', $v);
    $arr[$a[0]] = trim($a[1]);
    unset($arr[$k]);
}

print_r($arr);

Use explode within an interaction ( for ) by sweeping each line and transforming it into another array :

$dados = array
(
    0 => 'MemTotal:        4060964 kB',
    1 => 'MemFree:         3630320 kB',
    2 => 'MemAvailable:    3789472 kB',
    3 => 'Buffers:           93040 kB',
    4 => 'SwapCached:            0',
    6 => 'Active:           306312 kB'
);


$dadosNew = array();
foreach($dados as $key => $value)
{
    $valueNew = explode(":", $value);
    $dadosNew[$valueNew[0]] = trim($valueNew[1]);
}

var_dump($dadosNew);

Example